JPH0471086B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a supported transition metal catalyst. Specifically, the present invention relates to a method for producing a supported transition metal catalyst suitable for polymerizing α-olefins. Since the invention of the catalyst by Ziegler and Natsuta, various methods have been used to increase the yield of polyolefin per transition metal.Among them, the method proposed in Japanese Patent Publication No. 12105/1973 was to support titanium halide on a metal halide. This method of obtaining a catalyst can greatly increase the yield of polyolefin per transition metal, and many improved methods have been proposed. In particular, the improvement in catalyst performance over the past decade has been remarkable, and the yield of polyolefin per transition metal has improved.
The yield per transition metal catalyst (per catalyst including carrier) has been improved, and the transition metal catalyst has a high performance of tens of thousands of g/g per transition metal catalyst. Polyolefin polymerization is generally carried out in a slurry state in a liquid medium or a gaseous medium due to problems with solution viscosity and removal of polymerization heat. During polymerization in a slurry state, polyolefin exists in granular form, so it is better not to have large or fine particles.If there are large particles, they may get into the polymerization tank, piping, or other narrow parts of the equipment. In some cases, there was a problem of blockage. This clogging problem is a serious problem in continuous production methods such as polyolefin polymerization, which can lead to the shutdown of the entire plant. To deal with this problem, since the size of the transition metal catalyst and the size of the polyolefin particles are correlated, the transition metal catalyst may be classified to remove particles larger than a certain level. Among these, it is preferable to classify the carrier at the carrier stage because it is relatively easy to operate. However, when classified, carriers larger than a certain size are wasted, and since the carriers contain various organic substances, they must be disposed of as industrial waste, which is not preferable. The inventors of the present invention have conducted intensive studies on the above-mentioned problems, and have discovered that a transition metal catalyst can be obtained by carrying out a specific method without wasting the carrier, and have completed the present invention. An object of the present invention is to provide a method for efficiently producing a supported transition metal catalyst. The present invention provides a method for producing a supported transition metal catalyst by supporting a titanium halide on a carrier obtained by co-pulverizing a magnesium halide and an organic compound having a C-O bond. If the yield per transition metal catalyst is Wg/g, the particle size R of the co-pulverized product to be classified is:

With a carrier, the fine particles are classified into particles larger than R expressed by the formula, and the fine particles directly support titanium tetrachloride, and the coarse particles are co-pulverized with a halogenated hydrocarbon and then support titanium tetrachloride. A method for producing a transition metal catalyst. In the present invention, magnesium halides include magnesium chloride and magnesium bromide, with magnesium chloride being preferred. As the organic compound having a C-O bond, various compounds used in the production of known magnesium halide carriers can be used. For the co-pulverization method, various known devices and methods can be employed, but co-pulverization using a ball mill or a vibration mill is particularly preferred. In the present invention, the co-pulverized product obtained by the above operation is classified to separate coarse particles. The particle size of the co-pulverized material to be removed in this classification is 5 mm, since the coarse particle size of polyolefin, which is usually undesirable in the polymerization process, is 5 mm.
For example, if the yield of polyolefin is 20,000 g/g per supported transition metal catalyst, this corresponds to a particle size of the supported transition metal catalyst of approximately 0.1 mm.
Therefore, the yield per supported transition metal catalyst is, for example, W
g/g, the particle size R of the co-pulverized material to be classified and removed is

It is expressed as [Formula]. Many known methods can be used for classification, such as classification using a sieve with an appropriate opening;
Another example is classification using a classification cyclone using an air flow transport process. The co-pulverized product separated by classification and free of coarse particles supports titanium tetrachloride. On the other hand, the classified coarse particles are further pulverized using the aforementioned ball mill or vibration mill, etc. to make the coarse particles fine. At this time, if only the coarse co-pulverized particles are pulverized and polymerized using a catalyst obtained by supporting titanium tetrachloride, the number of ultrafine particles will increase, which is undesirable. The stereoregularity of the resulting polyolefin decreases. On the other hand, when coarse particles are co-pulverized in the coexistence of a halogenated hydrocarbon, the number of ultrafine particles hardly increases, the activity is improved, and the stereoregularity of the polyolefin obtained when used in the polymerization of α-olefins is also improved. Improves sex. The amount of the halogenated hydrocarbon added when co-pulverizing the coarse particles is about 0.01 to 0.5, preferably about 0.05 to 0.2, based on 1 part of the coarse particles.
The time required for co-pulverization varies depending on the shape of the crusher and cannot be specified, but 1/3 to 1/10 of the time required for the initial co-pulverization is sufficient. The halogenated hydrocarbons used include methylene chloride, ethylene dichloride, trichloroethane, propane chloride, dichloropropane, trichloropropane, α, α,
Aliphatic or aromatic halogenated hydrocarbons such as α-trichlorotoluene are used, but preferably those that are liquid at room temperature are used. By applying the method of the present invention, it is possible to provide a supported transition metal catalyst free of coarse particles in a higher yield, which is of high industrial value. EXAMPLES The present invention will be explained in more detail with reference to Examples below. Experimental example 1 a) Production of catalyst 30g of magnesium chloride containing 0.4Wt% water,
4.5 ml of ethyl orthoacetate and 3 ml of 1,2-dichloroethane were placed in a pot containing 80 stainless steel balls with a diameter of 12 mm and ground for 40 hours. This operation was repeated to obtain 1 kg of co-pulverized material. 0.074 for 500g of co-pulverized material
The co-pulverized material was placed on a wire mesh with a mesh opening of mm and separated into the upper and lower parts of the wire mesh while stirring. 65g was obtained on wire mesh. Using the crusher used above, place 20g on a wire mesh and 1.
Co-milling was carried out with 3 ml of 2-dichloroethane and only 20 g on a wire mesh for 5 hours each. Co-pulverized product obtained above, wire mesh bottom a, wire mesh top +
1,2-dichloroethane co-grinding b, grinding on wire mesh c, and wire mesh d, 10 g each.
Add 50% titanium tetrachloride to a 200ml round bottom flask.
Add 100 ml and treat at 80℃ for 1 hour with stirring.
The solid portion was washed 5 times with 100 ml of n-heptane, and after extracting the n-heptane, 50 ml of titanium tetrachloride was added and treated at 80°C for 1 hour with stirring, and then the solid portion was washed 7 times with 100 ml of n-heptane. After washing, 50 ml of n-heptane was added to prepare a supported transition metal catalyst. b) Polymerization reaction Prepare an autoclave with an internal volume of 5 that has been thoroughly dried and purged with nitrogen. Pour 50 ml of n-heptane in a 200 ml flask that has been thoroughly dried and purged with nitrogen, and add diethylaluminum chloride.
0.128 ml, methyl p-toluate 0.06 ml, triethylaluminum 0.008 ml, and the mixed catalyst slurry was added to the above autoclave. Next, 1.5 kg of propylene and 0.6 Nl of hydrogen were added, and the autoclave was heated. Polymerization was carried out at a temperature of 75°C for 2 hours. Next, unreacted propylene is discharged and the resulting polypropylene powder is taken out.
It was dried under reduced pressure at 60°C for 10 hours and weighed. In addition, the intrinsic viscosity of the powder (hereinafter abbreviated as η, measured with a tetralin solution at 135°C), the boiling n-heptane extraction residue rate (hereinafter abbreviated as η, extracted with boiling n-heptane for 6 hours using a Soxhlet extractor, extracted residual polymer weight/extraction) (Calculated as previous polymer weight x 100%), bulk specific gravity, and particle size distribution (Tyler Meshes, USA) were measured, and the results are shown in the table. Experimental Example 2 The same procedure as Experiment 1 was carried out except that co-pulverization was carried out using 30 g of magnesium chloride and 3 ml of ethyl benzoate.
It was about 10% on the wire mesh. Experimental Examples 3-b, 4-b The same procedure as Experimental Example 1-b was carried out except that 1,3-dichloropropane was used instead of 3 ml of 1,2-dichloroethane in Experimental Example 1-b (3-b). Experimental example 2-
In b, replace 3 ml of 1,2-dichloroethane with 1,
Experimental example 2 except that 1,1-trichloroethane was used.
-b The results are shown in the table (4-b).

【table】 [Brief explanation of the drawing]

FIG. 1 is a flow diagram to aid understanding of the present invention.

Claims (1)

[Claims] 1. In a method for producing a supported transition metal catalyst by supporting titanium halide on a carrier obtained by co-pulverizing magnesium halide and an organic compound having a C-O bond, co-pulverizing as a carrier If the yield per supported transition metal catalyst is Wg/g, the particle size R of the co-pulverized product to be classified is expressed by [Formula].It is classified into particles larger than R, and the fine particles directly support titanium tetrachloride. A method for producing a supported transition metal catalyst, characterized in that the coarse particles are co-pulverized by adding a halogenated hydrocarbon and then supported on titanium tetrachloride.